Sometimes during a class, people mention that they have trouble with peeling cupcake cases and hopefully the notes below might be of help:
The oven temperature has a part to play and sometimes, the temperature selected is not accurate. Use an oven thermometer to check. Lower and slower is a better way to bake.
When you are preparing your cupcakes, do not overbeat and fold in your flour by hand. An all in one recipe is not a good idea for cupcakes and ideally make them in small batches – 24 being the maximum.
It is also important to check the cupcakes are thoroughly cooked. The timings will depend on your oven but chocolate cupcakes usually take a little longer. A cake tester is a good way of checking that they are cooked through. If you open your oven door to check and they are not ready, close it really carefully so it does not bang. This shouldn’t affect your cakes.
Another reason why the cases might peel is because there is not enough mixture in the case. Again, the amount will vary with your oven – if the mixture is not rising to the top then add a little more and vice versa.
Remove the cupcakes from the tray as soon as you can pick them up. If you leave them in the tray they are still cooking and also steam is being created which can cause the cases to peel.
When the cupcakes are cool, it is best to avoid a plastic container and certainly do not put them in the fridge. Perhaps use the cake box that they are going to be delivered in and that works well. It is always a good idea to store them in a cooler room in the house.
Freezing cupcakes can sometimes cause a case to peel and this usually takes place when the cake is being defrosted.
Always try to use a cupcake case that you are happy with and you know has not peeled in the past.